The invention relates to a precipitation tube bundle for wet electrostatic filters, in particular for the precipitation of sulfur oxides and dust from exhaust gases. Filters of this kind consist of a bundle of plastic tubes which are connected to each other at their walls. In the center of each tube there is an electrode. During operation of the filter, the inner walls of the tubes are wetted with a flowing, electrically conductive washing fluid, and between the electrode and the wall of the tube a strong electrical field is generated. This electrical field causes an ionization of the exhaust gases so that they are electrically charged and migrate to the walls of the tubes thereby following the lines of electric flux. At these walls the charged exhaust gas particles are taken up by the washing fluid and transported to the outside via the ends of the tubes. In order to avoid electrical breakdowns, the tubes are grounded.
DE-A1-41 02 732 discloses precipitation tube bundles in which the individual tubes are bonded to each other on their external walls. It is a disadvantage of these precipitation tube bundles that individual precipitation tubes cannot be replaced without being damaged and that the connection of the individual tubes requires much work and material.
In contrast thereto, it is an object of the present invention to provide a precipitation tube bundle for wet electrostatic filters in which the individual tubes can be held replaceably and in a low-stress and very accurate-to-dimension manner.
This object is achieved with the features of the claims.
In achieving this object, the invention starts out from the basic idea of holding single-piece tubes in a form-fit connection by means of an upper support collar and a lower guide ring and, if necessary, a central guide ring. By means of the support collar the bundle of tubes can be suspended in a housing. The lower guide ring serves for spacing the tubes apart and for connecting the tube grounding to the outside. The center guide ring serves for spacing the tubes apart if the bundle of tubes is relatively long.
The invention has the following advantages.
By combining stable, low-stress and very accurate-to-dimension guide and support rings with the precipitation tubes, bundles of tubes having a continuously smooth wall can be produced, wherein the distance between the tubes is reduced to a minimum. Bundles of tubes of different materials can be produced, for example, the supporting construction can be made of a material different from that of the precipitation tubes. The precipitation tube bundles have tube walls being separated from each other so that, for example, in case of voltage flashovers only the relevant tube is damaged. If they are damaged, the precipitation tubes can easily be replaced. Different kinds of grounding can easily be inserted in the precipitation tube bundles. The grounding can be prefabricated and easily be replaced or repaired in case of damage. The precipitation tube bundles can be produced more easily and cost-efficiently. In contrast to bundles consisting of connected half-tube elements, in the present invention there are no splits and/or borderings.